A reader of the blog, Olov, has produced the following video. He calls this a “Living Sankey Diagram”. The background can be found on the Sweco Blog (in Swedish). Basically he suggests to take energy declarations for buildings (‘Energideklarationen’) one step further and have visual energy monitoring for building using realtime data.

Energy consumption of a house is shown over a period of a year with up to 3 or 4 datasets per day. We can see heat (red) and electricity (orange). Not sure about the temperature indication at the top left, possibly meant to be the difference to a default temperature (Olov, if possible, please explain by commenting below).

Main consumers in the building are hot water generation (‘Tappvarmvatten’), room heating (‘Radiatorer’), ventilation and cooling. Some PV cells (‘Solceller’) at times add to the purchased energy (‘Köpt Energi’). The pink flow shows heat recovery (‘Värmeåtervinning’). The building is classified in energy class B.

Here, a data series has been used to produce the Sankey diagrams and then the frames were converted to a video. This makes for a nice effect and allows watching your energy flows in retrospect. For example, the PV cells feed energy mostly during the months, while in the same period heat demand and recovery is very limited.

This was apparently produced using e!Sankey. To really do an energy monitoring and produce the Sankey diagram every couple of minutes, there is a software development kit (SDK) the allows linking to a data source (energy measurement data) and pushing the “living Sankey diagram” to a website. Another example can be found here.

From my collection of Sankey diagrams here are three very similar samples depicting energy flows in a building. All three are from Germany (did I mention that more than half of the Sankey diagrams seem to be from Germany or Austria?).

These are all very simple Sankey diagrams. This first one is a hand-drawn goodie from the times when reports were still done with a typewriter. It shows use of fuel oil (‘Heizol’) in a school building, and interesting to see, the flows are given in kilograms fuel oil rather than to represent the heating value. The school building consumes 80 tonnes of fuel oil per year.

Note that flows are not to scale (arrow for equivalent of 10580 kg fuel oil annual heat loss through walls is about the same width as the one representing 31770 kg heat loss through windows). So this Sankey diagram doesn’t deserve an A…

The next building energy flow Sankey diagram shows flows in Watts (W). Not sure where I found this one. Flows again are not proportional (spot the 470 W flow and compare it to the others). Main inputs are radiation (‘Strahlung’) and electric energy. A heat pump cycling energy can be seen, so it seems that this one is maybe for a passive house.

This last one done with a Sankey diagram software hence flows are to scale in this one (although I have some doubts regarding the width of the fuel oil input arrow on the left). Flows are in kWh per year. Main fuel type is natural gas (red), some district heating (blue). Electric energy in yellow, consumed by IT, lighting, air compressors, and so on. This energy flow Sankey diagram is probably for a factory building or complex.

I will try to add the sources where I found these three diagrams. Please forgive my negligence this time.

This post on the Transsolar ‘Green & Sexy’ blog features two Sankey diagrams. The “climate engineers” at Transsolar use them to model heat flows inside a building based on outside temperature and solar radiation.

No absolute values are given in these demo Sankey diagrams, but one can still get a general idea by observing proportions. Flows are color-coded with solor radiation in yellow, convection in blue, and heat losses in red.

The second Sankey diagram shown is a timeline made 24 frames – one per hour over a full-day. As the outside temperature rises and solar radiation increases around noon, the inside temperature and cooling demand increases.

(via tumblr)

The authors explain:

“These Sankey diagrams allow us to see the proportion of how much energy is hitting the facade, how much energy is being radiated into the walls, how much energy is being convected into the air, and how much heating or cooling is actually needed to maintain an acceptable indoor air temperature. The animation is the first example we’ve ever seen of a Sankey diagram that represents the dynamic, ever-changing relationship of heat flows in a building with time.”

Nicely made infographic from steelconstruction.info wiki. What happens to the building materials on demolition, how much of concrete, timber and steel can be recycled?

The three arrows are curved and start at a 7-o’clock position. Used concrete from building demolition is mostly downcycled. Wood from structural frames is mostly landfilled, or re-used. Steel has a very good recyclability and most of the material can be recovered to make new steel.

The view angle and the images of construction machines make it a very attractive infographic.

Both Sankey diagrams are built up the same way. The top part of each diagram shows electricity generation, the bottom part the energy flows for heating. Significant conversion and transmission losses can be identified by the arrow branching out at the top. Flows from the left represent the energy sources: coal (brown), natural gas (blue), biomass/solar (green). To the right the flows are broken down to the individual consumption, such as heating, cooling, lighting, other electric appliances, etc.

This article on ‘A Pilot for Measuring Energy Retrofits’ describes how researchers from the EEB Hub used an old navy building in Philadalphia to “determine detailed system performance”.

EEB Hub researchers outfitted Building 101 with sensors and a data acquisition system to determine detailed system performance, building energy loads, indoor environmental quality (IEQ), and a detailed operation of the building control system. … The sensors read data from 509 sensing points, collecting 1,048 pieces of data at one-minute intervals. These data points track indoor air quality, occupant comfort, and building energy use.

The result of that “inverse modelling” (i.e. measuring) approach are presented in Sankey diagrams and are used “to identify discrepancies in the predicted versus actual energy balance”.

There are significant differences between the January energy use…

… and the energy picture in July

While in winter mainly natural gas is used for heating, the gas consumption in summer is down. In July electricity consumption is significantly higher due to air conditioning.

Unfortunately no unit of measurement is given (it could be kWh), but nevertheless proportions of the energy flows are correct.

The flows represent the heat energy. Overall demand for heat 37.46 kWh per square meter per year. 12.08 kWh/m2a is from solar panels, 25.38 kWh/m2a from an air-source heat pump (whaterver that is…).

Untypical Sankey diagram, but nevertheless interesting. Flows are not really to scale (compare the 12 kWh inflow and the 6 kWh losses outflow, which should have half the width, or to the 25 kWh inflow that should be roughly twice as wide). Unicolor grey flows with a slight gradient from left to right.